memcg: remove pcp_counter_lock

Commit 733a572e66d2 ("memcg: make mem_cgroup_read_{stat|event}() iterate
possible cpus instead of online") removed the last use of the per memcg
pcp_counter_lock but forgot to remove the variable.

Kill the vestigial variable.

Signed-off-by: Greg Thelen <>
Acked-by: Michal Hocko <>
Acked-by: Johannes Weiner <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
2 files changed